Brine making tanks, also referred to herein as brine tanks, are used for various purposes, such as, for example, water softening. Such a tank is filled with salt and water to make brine. A commercial/industrial brine tank may be of any varying size according to requirements, with one example being about ten feet in height and fifteen feet diameter. Such a tank can hold about twenty-five tons of salt. The tank is periodically filled with water to form brine. Each time water is filled to the tank, a proportionate amount of salt is dissolved to gradually decrease level of salt in the tank. Once the salt has been dissolved, then it is necessary to refill the tank with salt.
It is important to know when the tank must be refilled with salt. Various procedures have been tried to gauge salt depth in brine tanks. These attempts have been made either on or in the brine tank itself.
One known system for monitoring salt level includes external markings on the tanks. However, due to variations in tank opacities, determining salt level and brine level can be unreliable. Ultrasonic devices have also been used. However, salt and water releases dissolved oxygen and tends to float certain air born insolubles into a foam on top of the liquid level. The ultrasonic device bounces a signal off of the top layer of the foam and cannot read the salt layer beneath the foam. The ultrasonic devices cannot differentiate between the semi-solid salt and the foam covering the liquid surface.
High intensity lamps may be used to illuminate the brine. However, salt when blown into the tanks may coat the lights and create high maintenance requirements as the lights must be cleaned often. The lights also add a great deal of heat into the enclosed space of the tanks. Plumb bob level indicators have been tried and are reasonably effective as long as an operator does not lower the plumb bob while filling the tank with salt. This leaves the plumb bob locked into the salt at a low point in the tank and cannot give a signal as long as it is buried in the salt. Finally, sight glasses have been tried but have two inherent problems. The first is that sight glasses are subject to breakage which drains the tank of all liquid brine. The second is that the salt tends to fill up the sight glass and requires periodic flushing to clear the column.
The present invention is directed to overcoming one or more of the problems discussed above in a novel and simple manner.